Here are mine and the associated day-dreams:
Mid 1970's Jaguar XJ6-C (XJ6 coupe, not an XJS) back-date the body work to look like a Series 1 XJ6 (1967-72 I think), add BMW 5-speed manual and Webers to the straight six, widened steel wheels to look like C-Type racing wheels
European Mercedes 280SL or 300SL (1972-89 R107 body style), add 1980's-era 17" AMGs, 5-speed manual from a W124 300E and the 3.6L 276hp straight six from a 1990's C36 AMG
1985-7 A2-chassis GTI, 1.8L 16V head on 2.0L (16V) early-90's Passat lower end, CIS injection (= 16V top-end with torque like an 8V - I've done this, I wish I had never sold that car!!)
VW Cabriolet up to 1992 with 2.0L 16V/CIS as above, Scirocco 16V suspension and brakes, Euro bumpers, old BBS ground effects
More realisitically:
Finish my 1984 911 Carrera (and paint it any color but its current shade of brown)
Make my 1977 924 nice enough to make the wife want to ride in it (or at least tolerate it)
Restore my 1972 VW Super Beetle (my first car) that's been sitting for 25 years